YES We show the termination of the TRS R: app(app(plus(),|0|()),y) -> y app(app(plus(),app(s(),x)),y) -> app(s(),app(app(plus(),x),y)) app(app(times(),|0|()),y) -> |0|() app(app(times(),app(s(),x)),y) -> app(app(plus(),app(app(times(),x),y)),y) app(app(map(),f),nil()) -> nil() app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) inc() -> app(map(),app(plus(),app(s(),|0|()))) double() -> app(map(),app(times(),app(s(),app(s(),|0|())))) Instead we prove termination of the uncurried system: app(cons_0(),y) -> cons_1(y) app(cons_1(x1),y) -> cons_2(x1,y) app(map_0(),y) -> map_1(y) app(map_1(x1),y) -> map_2(x1,y) app(plus_0(),y) -> plus_1(y) app(plus_1(x1),y) -> plus_2(x1,y) app(s_0(),y) -> s_1(y) app(times_0(),y) -> times_1(y) app(times_1(x1),y) -> times_2(x1,y) plus_2(|0|_0(),y) -> y plus_2(s_1(x),y) -> s_1(plus_2(x,y)) times_2(|0|_0(),y) -> |0|_0() times_2(s_1(x),y) -> plus_2(times_2(x,y),y) map_2(f,nil_0()) -> nil_0() map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) inc_0() -> map_1(plus_1(s_1(|0|_0()))) double_0() -> map_1(times_1(s_1(s_1(|0|_0())))) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(map_1(x1),y) -> map_2#(x1,y) p2: app#(plus_1(x1),y) -> plus_2#(x1,y) p3: app#(times_1(x1),y) -> times_2#(x1,y) p4: plus_2#(s_1(x),y) -> plus_2#(x,y) p5: times_2#(s_1(x),y) -> plus_2#(times_2(x,y),y) p6: times_2#(s_1(x),y) -> times_2#(x,y) p7: map_2#(f,cons_2(x,xs)) -> app#(f,x) p8: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(map_0(),y) -> map_1(y) r4: app(map_1(x1),y) -> map_2(x1,y) r5: app(plus_0(),y) -> plus_1(y) r6: app(plus_1(x1),y) -> plus_2(x1,y) r7: app(s_0(),y) -> s_1(y) r8: app(times_0(),y) -> times_1(y) r9: app(times_1(x1),y) -> times_2(x1,y) r10: plus_2(|0|_0(),y) -> y r11: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r12: times_2(|0|_0(),y) -> |0|_0() r13: times_2(s_1(x),y) -> plus_2(times_2(x,y),y) r14: map_2(f,nil_0()) -> nil_0() r15: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r16: inc_0() -> map_1(plus_1(s_1(|0|_0()))) r17: double_0() -> map_1(times_1(s_1(s_1(|0|_0())))) The estimated dependency graph contains the following SCCs: {p1, p7, p8} {p6} {p4} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(map_1(x1),y) -> map_2#(x1,y) p2: map_2#(f,cons_2(x,xs)) -> map_2#(f,xs) p3: map_2#(f,cons_2(x,xs)) -> app#(f,x) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(map_0(),y) -> map_1(y) r4: app(map_1(x1),y) -> map_2(x1,y) r5: app(plus_0(),y) -> plus_1(y) r6: app(plus_1(x1),y) -> plus_2(x1,y) r7: app(s_0(),y) -> s_1(y) r8: app(times_0(),y) -> times_1(y) r9: app(times_1(x1),y) -> times_2(x1,y) r10: plus_2(|0|_0(),y) -> y r11: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r12: times_2(|0|_0(),y) -> |0|_0() r13: times_2(s_1(x),y) -> plus_2(times_2(x,y),y) r14: map_2(f,nil_0()) -> nil_0() r15: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r16: inc_0() -> map_1(plus_1(s_1(|0|_0()))) r17: double_0() -> map_1(times_1(s_1(s_1(|0|_0())))) The set of usable rules consists of (no rules) Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: app#_A(x1,x2) = x2 + 3 map_1_A(x1) = 1 map_2#_A(x1,x2) = x2 + 2 cons_2_A(x1,x2) = x1 + x2 + 4 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: app#_A(x1,x2) = max{0, x1 - 8, x2 - 1} map_1_A(x1) = x1 + 7 map_2#_A(x1,x2) = max{0, x1 - 8, x2 - 10} cons_2_A(x1,x2) = max{x1 + 9, x2 + 9} app#!_A(x1,x2) = max{4, x1 - 3, x2 - 1} map_1!_A(x1) = max{2, x1 - 36} map_2#!_A(x1,x2) = max{3, x1 + 1} cons_2!_A(x1,x2) = max{0, x1 - 12} partial status: pi(app#) = [2] pi(map_1) = [] pi(map_2#) = [] pi(cons_2) = [2] The following rules are removed: p1, p2, p3 Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: times_2#(s_1(x),y) -> times_2#(x,y) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(map_0(),y) -> map_1(y) r4: app(map_1(x1),y) -> map_2(x1,y) r5: app(plus_0(),y) -> plus_1(y) r6: app(plus_1(x1),y) -> plus_2(x1,y) r7: app(s_0(),y) -> s_1(y) r8: app(times_0(),y) -> times_1(y) r9: app(times_1(x1),y) -> times_2(x1,y) r10: plus_2(|0|_0(),y) -> y r11: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r12: times_2(|0|_0(),y) -> |0|_0() r13: times_2(s_1(x),y) -> plus_2(times_2(x,y),y) r14: map_2(f,nil_0()) -> nil_0() r15: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r16: inc_0() -> map_1(plus_1(s_1(|0|_0()))) r17: double_0() -> map_1(times_1(s_1(s_1(|0|_0())))) The set of usable rules consists of (no rules) Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: times_2#_A(x1,x2) = x1 s_1_A(x1) = x1 + 2 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: times_2#_A(x1,x2) = 0 s_1_A(x1) = max{4, x1 - 6} times_2#!_A(x1,x2) = max{7, x1 - 33, x2 - 1} s_1!_A(x1) = max{6, x1 - 33} partial status: pi(times_2#) = [1] pi(s_1) = [1] The following rules are removed: p1 Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: plus_2#(s_1(x),y) -> plus_2#(x,y) and R consists of: r1: app(cons_0(),y) -> cons_1(y) r2: app(cons_1(x1),y) -> cons_2(x1,y) r3: app(map_0(),y) -> map_1(y) r4: app(map_1(x1),y) -> map_2(x1,y) r5: app(plus_0(),y) -> plus_1(y) r6: app(plus_1(x1),y) -> plus_2(x1,y) r7: app(s_0(),y) -> s_1(y) r8: app(times_0(),y) -> times_1(y) r9: app(times_1(x1),y) -> times_2(x1,y) r10: plus_2(|0|_0(),y) -> y r11: plus_2(s_1(x),y) -> s_1(plus_2(x,y)) r12: times_2(|0|_0(),y) -> |0|_0() r13: times_2(s_1(x),y) -> plus_2(times_2(x,y),y) r14: map_2(f,nil_0()) -> nil_0() r15: map_2(f,cons_2(x,xs)) -> cons_2(app(f,x),map_2(f,xs)) r16: inc_0() -> map_1(plus_1(s_1(|0|_0()))) r17: double_0() -> map_1(times_1(s_1(s_1(|0|_0())))) The set of usable rules consists of (no rules) Take the reduction pair: generalized weighted path order (>=MG, >G) base order 1: matrix interpretation with standard point-wise order: carrier: N^1 order: standard order interpretations: plus_2#_A(x1,x2) = x1 s_1_A(x1) = x1 + 2 base order 2: marked-algebra reduction triple (>=A, >=A!, >A!): max/plus interpretation on natural numbers: plus_2#_A(x1,x2) = 0 s_1_A(x1) = max{4, x1 - 6} plus_2#!_A(x1,x2) = max{7, x1 - 28, x2 - 1} s_1!_A(x1) = max{6, x1 - 28} partial status: pi(plus_2#) = [1] pi(s_1) = [1] The following rules are removed: p1 Then no dependency pair remains.